— Not at all. I'd be happy to.
A:Isn't it very cold today?
B:Are you feeling ill today?
C:Would you mind opening the window?
D:Have you bought the kite to me?
(Ⅰ)判断函数f(x)的单调性,并说明理由
(Ⅱ)若x∈1,2,不等式f(x)≥e﹣x恒成立,求a的取值范围.
如图,在△ABD中,C是BD上一点,若E、F分别是AC、AB的中点,△DEF的面积为4.5,则△ABC的面积为 ____.
如图,在Rt△ABC中,∠C=90°,AC=4cm,BC=3cm,将△ABC沿AB方向向右平移得到△DEF,若AE=8cm,DB=2cm.
(1)求△ABC向右平移的距离AD的长;
(2)求四边形AEFC的周长.